The invention relates to a system for a waste paper conditioning, and more specifically, to a system for waste paper conditioning having a secondary pulper.
German Patent Disclosure No. 25 14 162 (U.S. Pat. No. 4,017,033) shows a system for waste paper conditioning utilizing a secondary pulper wherein this arrangement serves to pass the fraction drawn from the secondarv pulper, which is enriched with heavy dirt, into a hydrocyclone. The accepted stock removed from the hydrocyclone is then returned to the primary pulper.
In another system for waste paper conditioning shown in German Patent Document No. 27 59 113, (U.S. Pat. No. 4,231,526) the fraction enriched with light dirt and the fraction with heavy dirt pass through the hydrocyclone and are discharged from the secondary pulper. These fractions are subjected to several purification stages wherein accepted stock produced in the interim is routed to an accepted stock vat, and finally, a residual portion heavily laden with dirt is routed back to the primary pulper.
As can be appreciated, it is very expensive to design a system such as that described above for performing the necessary processing steps until the accepted stock has been reasonably rid of dirt and a residual portion of fiber suspension, which is relatively heavily laden with dirt, is obtained and returned to the pulper. It was previously suggested to separate the dirt through a wash filter and pass it to a decker, but the heavy dirt was to be passed from the secondary pulper to the wash filter in a separate phase which would require a certain expense for switching and controlling the slides.
It would thus be desirable to provide an improved waste paper conditioning system which is simplified and inexpensively designed.